Hello, I was trying to sim
 

Hello,
I was trying to simulate a couple of flow cases through hydraulic valves. My first tests worked out fine (simulations to within 1.5 to 2 l/min of measurements), and then I started doing further simulations with smaller systems, and with valves in situations where the spool is only around 0.2 to 0.4mm open.

In these cases, I started seeing an effect, where, just downstream from the regions with the highest velocity, there is a sudden discontinuity in the velocity field, in which the velocity drops to zero, and further downstream the flow shows up again.

I initially thought my mesh was too coarse, and I tried with another mesh of roughly double the number of cells, and higher mesh grading, but the results were more or less the same.

I took a couple of screen shots from Paraview, and shall try to attach one of them here (havent been successful before!). In case I am unable to attach it here, is there another option?

http://www.cfd-online.com/OpenFOAM_D...your_image.gif

Does anyone have any suggestions as to what the problem might be?

Thanks, and have a nice week ahead!

Philippose

http://www.cfd-online.com/Open
 

http://www.cfd-online.com/OpenFOAM_D...your_image.gif

Ok... Trying now from firefox
 

Ok... Trying now from firefox 2.0 in Windows :-) I hope it works this time! If not, I have only one more option... to try Internet Explorer...!

http://www.cfd-online.com/OpenFOAM_D...your_image.gif

Philippose

My last try... from Internet E
 

My last try... from Internet Explorer.... I apologise again for flooding the group...

http://www.cfd-online.com/OpenFOAM_D...ges/1/3328.jpg

Philippose